The vegetation of the Sant valley in South Khangai

Pacyna, Anna

doi:10.1002/fedr.4910960515

Cited by 2 publications

(2 citation statements)

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“…The Mongolian Steppe is one of the largest remaining grassland ecosystems in the world (Kawamura et al ., ) spanning an area of about 1.17 million square kilometers (Fernandez‐Gimenez & Allen‐Diaz, ) and encompassing roughly 2.6% of the global grassland vegetation (Li et al ., ). While Mongolia's vegetation has been described in general (Kalinina, ; Lavrenko & Karamysheva, ) and some plant communities have been studied (Pacyna, ; Wallis de Vries et al ., ), relatively little is known about the ecosystems vulnerability to human activity and climate change (Sugita et al ., ). Recent decades have seen significant decline in grasslands across the country (Ykhanbai et al ., ) and over 70% of the steppe is now considered degraded (UNEP, ).…”

Section: Introductionmentioning

confidence: 99%

Satellite observed widespread decline in Mongolian grasslands largely due to overgrazing

Hilker

Natsagdorj

Waring

et al. 2013

Global Change Biology

255

158

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The Mongolian Steppe is one of the largest remaining grassland ecosystems. Recent studies have reported widespread decline of vegetation across the steppe and about 70% of this ecosystem is now considered degraded. Among the scientific community there has been an active debate about whether the observed degradation is related to climate, or over-grazing, or both. Here, we employ a new atmospheric correction and cloud screening algorithm (MAIAC) to investigate trends in satellite observed vegetation phenology. We relate these trends to changes in climate and domestic animal populations. A series of harmonic functions is fitted to Moderate Resolution Imaging Spectroradiometer (MODIS) observed phenological curves to quantify seasonal and inter-annual changes in vegetation. Our results show a widespread decline (of about 12% on average) in MODIS observed normalized difference vegetation index (NDVI) across the country but particularly in the transition zone between grassland and the Gobi desert, where recent decline was as much as 40% below the 2002 mean NDVI. While we found considerable regional differences in the causes of landscape degradation, about 80% of the decline in NDVI could be attributed to increase in livestock. Changes in precipitation were able to explain about 30% of degradation across the country as a whole but up to 50% in areas with denser vegetation cover (P < 0.05). Temperature changes, while significant, played only a minor role (r(2) = 0.10, P < 0.05). Our results suggest that the cumulative effect of overgrazing is a primary contributor to the degradation of the Mongolian steppe and is at least partially responsible for desertification reported in previous studies.

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Section: Introductionmentioning

confidence: 99%

Satellite observed widespread decline in Mongolian grasslands largely due to overgrazing

Hilker

Natsagdorj

Waring

et al. 2013

Global Change Biology

255

158

View full text Add to dashboard Cite

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“…Mongolia's vegetation has been described in general (Kalinina 1974; Yunatov 1977; Ulziikhutag 1989; Lavrenko & Karamysheva 1993). Some plant communities have been classified (Pacyna 1986; Hilbig 1995; Wallis de Vries, Manibazar & Dugerlham 1996) and the seasonal production dynamics of several communities have been studied (Breymeyer & Klimek 1983; Tsogoo 1990; Lavrenko & Karamysheva 1993). However, few experimental or observational studies have been conducted to determine the effects of grazing (or release from grazing) on vegetation productivity or species composition.…”

Section: Introductionmentioning

confidence: 99%

Testing a non‐equilibrium model of rangeland vegetation dynamics in Mongolia

Fernández‐Giménez

Allen-Díaz

1999

Journal of Applied Ecology

267

171

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Summary1. Few studies have tested the applicability of current non-equilibrium models of rangeland vegetation dynamics to a particular ecosystem, or across a range of systems that might be expected to respond di erently to grazing. This study assessed the extent to which the non-equilibrium persistent (NEP) model of rangeland vegetation dynamics applies to three distinct Mongolian rangeland ecosystems, the desert-steppe, steppe and mountain-steppe. 2. Standing biomass, vegetation cover and composition, and species richness and diversity were examined along grazing pressure gradients in ecological zones of differing productivity and interannual variability in precipitation. 3. In the desert-steppe, biomass, functional group cover, richness and diversity did not vary along grazing pressure gradients, but all vegetation variables except the cover of weedy annuals and unpalatable forbs varied signi®cantly between years. Vegetation dynamics in this zone largely conformed to the NEP model of rangeland dynamics. 4. In the mountain-steppe, grass and total biomass, total vegetative cover, the cover of grasses, weedy annuals and unpalatable forbs, and richness and diversity varied along grazing pressure gradients. With increasing grazing pressure, grasses decreased and forbs and weedy annuals increased, as the conventional range condition (RC) model predicts. Interannual variation in precipitation in¯uenced total vegetative cover, species and functional group cover, and richness and diversity. 5. In the steppe, forb biomass, grass, forb, unpalatable forb and weedy annual cover, and diversity varied along grazing pressure gradients. Grass biomass and total vegetative cover responded interactively to rainfall and grazing. Forb biomass, grass, forb and weedy annual cover and richness varied between years. Grasses decreased and forbs and weedy annuals increased with increasing grazing pressure, conforming to the RC model. 6. Ecosystem response to rainfall and grazing is complex, and interpretation of the response depends on the speci®c variables examined. The recent paradigm shift in rangeland science from the RC model to non-equilibrium models has been embraced with such enthusiasm by some that the concept of non-equilibrium rangelands may be as much in danger of being misapplied as equilibrium-based models have been.

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The vegetation of the Sant valley in South Khangai

Cited by 2 publications

References 0 publications

Satellite observed widespread decline in Mongolian grasslands largely due to overgrazing

Satellite observed widespread decline in Mongolian grasslands largely due to overgrazing

Testing a non‐equilibrium model of rangeland vegetation dynamics in Mongolia

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